Ab-initio study of the Y adsorption and YN formation on the GaN(000(1)over-bar): Diffusion pathways and stability

作者：Guerrero Sanchez J^*; Cocoletzi Gregorio H; Rivas Silva J F; Takeuchi Noboru

来源：Superlattices and Microstructures, 2016, 96: 67-74.

DOI：10.1016/j.spmi.2016.05.007

• Gallium nitride
• Yttrium nitride
• Bilayer formation
• Diffusion pathways
• Surface formation energy

Yttrium (Y) adsorption and yttrium nitride (YN) thin film formation on the GaN(000 (1) over bar) surface are investigated using first principles total energy calculations. Results show that for Ga rich conditions the most stable configuration for Y adsorption is at a Bridge site. Nudged elastic band calculations show that the Y diffusion through the GaN surface is possible with low energy barriers. However, the most stable configuration corresponds to the geometry in which the Y atom migrates in to the first layer, forming an YN pair and displacing a Ga atom to the T4(2) site. Also, it is found that the increase of Y atoms up to a full monolayer is not energetically favorable, then the formation of an Y layer on top of the surface is not possible. However, under N-rich conditions the formation of a cubic-like YN bilayer above the surface becomes stable. Total and partial density of states show that the formation of YN on top of the Ga-terminated surface modify the electronic properties. Nevertheless, metallic behavior remains after YN formation.

• 出版日期2016-8